Devices help city track sewage overflow

By Jennifer Pritchett

The City of Kingston has installed new monitors on its sewers that has revealed the municipality spews millions more litres of untreated sewage into area waterways each year than previously documented.

Since January 2007, the city has discharged 39 million litres - enough to fill 488 backyard swimming pools - of the foul liquid into Lake Ontario and other watercourses from pipes that had never before been monitored.

Still, at least 18 sites don't yet have the monitoring devices to track how much more raw waste flows into the waterways.

"The monitoring is to get a good indication of how we can engineer out the problem," said Jim Keech, president of Utilities Kingston.

The city plans to install six more monitoring devices in the coming months.

Kingston's longstanding practice of intentionally sending untreated waste into local waterways is the unfortunate result of a century-old system that becomes overloaded during heavy rain.

The combined sewer pipes, which carry both runoff from roads and raw sewage, can't move the waste fast enough to the Ravensview treatment plant. And so, the system is designed to purge the overflow into local waterways to prevent the waste from backing up into people's basements and toilets.

Until about a year ago, the city only monitored the untreated waste coming from seven pumping stations.

But new equipment installed at 11 of the combined sewer manholes that can direct waste directly into Lake Ontario, the Cataraqui River and other waterways, have enabled Utilities Kingston staff to collect data on how much untreated waste is purged from pipes that weren't monitored before.

"It's a lot, but it's not as much as had been going out [from the pumping stations]," said Keech, president of Utilities Kingston.

The new ultrasonic devices cost about $10,000 and measure the amount of liquid moving out of the pipe into the watercourse. The city is also looking at installing storage tanks at several of the locations in order to trap the waste during heavy rain and prevent it from spewing into the water. Another solution may be to expand the size of the trunk sewers in those areas to enable the waste to flow more easily to the treatment plant.

"We're trying to be proactive," said Keech. "And what is going out, it's not raw sewage. It's a lot of rain water."

Mark Mattson of the environmental group Lake Ontario Waterkeeper was pleased to hear of the new monitoring devices because it helps to give a clearer picture of the volume of waste being directed into waterways.

"A big part of what we're trying to do to this point is to get the best information available so we can look at what corrections need to be made," he said. "These new monitoring devices the city put in place are really an important step in getting that information."

Still, Mattson said more work needs to be done to decrease the pollution caused by bypasses.

"We want to see what sort of impact that waste is having on the river," he said.

Organizations such as Lake Ontario Waterkeeper and the Canadian Environmental Law Association have been working with the Ministry of the Environment for years to require the City of Kingston and other cities with aging infrastructure to decrease the amount of untreated sewage going into watercourses.

Over the past five years, roughly $160 million - including the $116 million, not-yet-completed retrofit of the Ravensview treatment plant - has been spent in Kingston to decrease the number of bypasses.

For the first eight months of 2007, the total amount of untreated waste that went into the waterways from the pumping stations (3,568,000 litres) and the newly monitored sewage pipes (39,063,000 litres) is 42.6 million litres.

That amount represents 0.25 per cent of the roughly 17 billion litres of raw sewage and road run-off generated in Kingston so far this year, according to data released by the City of Kingston.

"That's a real surprise to me," said Mattson.

"Both the Canadian Environmental Law Association and Lake Ontario Waterkeeper will have to look at those numbers to see if that's a fair calculation in terms of what the city isn't treating. It just appears on the surface to be a very small amount, meaning that the city is basically treating all of its sewage."

However, Mattson said it is great news if what the city has done under the guideline of the ministry and the encouragement of groups such as Lake Ontario Waterkeeper has resulted in a major improvement.

"Kingston is clearly ahead of the curve in terms of monitoring, compared to other cities who have bypasses," he said. "We're going to have to look at those numbers though."

Keech admitted he too was surprised by the percentage of waste the city didn't treat and said the number would have been much higher in the years prior to the sewer system upgrades.

Indeed, so far this year, the volume of untreated waste going into waterways is way down, compared to last year and previous years.

In 2006, the city spilled nearly 140 million litres of raw waste into area waterways, compared to 126 million in 2005.

Keech said that even though fall can be a heavy rain period, the current total of 42.6 million litres for 2007 has a long way to go before it surpasses the volumes for any recent years.

"I think we've made some amazing upgrades," he said.

Keech said the reduction in volume in 2007 can be directly attributed to the recent infrastructure improvements to the sewer system.

Some of those improvements include two new sewage pipes crossing the Cataraqui River to transport waste to the Ravensview treatment plant and the installation of a second Harbourfront trunk sewage pipe to run alongside the old one from Princess Street along Wellington Street to the River Street pumping station.

The city has rebuilt the North End pumping station, as well as cleared the North End trunk sewer and the old Harbourfront trunk sewer. Prior to the cleaning, parts of the North End trunk sewer was blocked so badly that only 20 per cent of the pipe was able to be used.

The city has also built two large underground storage tanks, one at the foot of Collingwood Street and the other at Emma Martin Park at the bottom of Cataraqui Street. Those tanks store waste during heavy rain until the system can handle it.

jpritchett@thewhig.com